Leidenfrost Dynamics

Supplementary Data

• Supplemental Video 1: Water drops falling on a hot plate (at a temperature of 300°C). These drops are in the Leidenfrost state, as shown by their shape (quasi-spherical), the absence of boiling, and a very high mobility. Credits: Marc Fermigier, Christophe Clanet, and David Quéré. Download video file (MOV)

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  Supplemental Video 2: Hot steel ball (diameter of 15 mm) magnetically maintained in FC-72, a fluorinated liquid boiling at 56°C. For a ball temperature larger than the Leidenfrost temperature T_L (130°C for this system), a film of vapor forms (inverse Leidenfrost phenomenon). This film drains upwards, generating ripples and bubbles at the upper pole. After 30 s, the ball temperature reaches T_L, which produces an explosive release of bubbles. Credits: Ivan Vakarelski and Siggi Thoroddsen. Download video file (MOV)

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  Supplemental Video 3: Side view of a large Leidenfrost drop, just above the threshold size of destabilization: A chimney of vapor rises at the center and makes the dome above the liquid. When this dome bursts, a liquid torus transiently forms, and closes, which produces an eruption above the puddle. Spectacular oscillations follow. The movie is slowed down by a factor of 100. Credits: Dan Soto and Raphaële Thévenin. Download video file (AVI)

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  Supplemental Video 4: Top view of the destabilization of a large Leidenfrost drop: Above a threshold in size, a chimney forms at the center of the drop. As it closes (and later reappears), the drop oscillates. Credits: Marc Fermigier, Christophe Clanet, and David Quéré. Download video file (MOV)

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  Supplemental Video 5: A Leidenfrost drop running on a plate with crenelations slows down on centimeter-size distances instead of meters on a flat solid. The distance between two crenels is 1.5 mm, and the depth is 250 µm. The enhanced friction is attributed to the successive (soft) impacts of the bumps below the drop onto the sides of the crenelations. Credits: Guillaume Dupeux and Marie le Merrer. Download video file (AVI)

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  Supplemental Video 6: Combined videos showing the fall of a centimeter-size steel sphere at 25°C (on the left), 110°C (in the middle), and 180°C (on the right). At 110°C, there is an intensive bubble release (this temperature is above the boiling point of liquid, here FC-72 like in Supplemental Video 2). At 180°C, there is a continuous vapor film (it is above the Leidenfrost temperature), which makes its final fall velocity much higher than in the other cases. The movie is slowed down by a factor 30. Credits: Ivan Vakarelski and Siggi Thoroddsen. Download video file (MOV)

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  Supplemental Video 7: Rebounds on a water drop on a hot solid at Weber numbers smaller than unity: The rebounds are nearly elastic. Credits: Anne-Laure Biance, Christophe Clanet, and David Quéré. Download video file (AVI)

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  Supplemental Video 8: Rebounds on a water drop on a hot solid at Weber numbers larger than unity: Rebounds are less elastic, and strong vibrations are generated by the impacts. Credits: Anne-Laure Biance, Christophe Clanet, and David Quéré. Download video file (AVI)

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  Supplemental Video 9: Impact of a water drop at We = 16 on a solid at 300°C. Although the temperature is much higher than the static Leidenfrost temperature (about 160°C), contact exists between the solid and liquid at impact, as revealed by the intense production of droplets. (This corresponds to the contact-boiling-regime data in Figure 8.) Credits: Tuan Tran and Detlef Lohse. Download video file (MOV)

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  Supplemental Video 10: Impact of a water drop at We = 16 on a solid at 380°C. The droplet ejection is no longer observed: This defines a dynamical Leidenfrost situation, in which there is no contact with the plate despite the impact. (This corresponds to the film-boiling-regime data in Figure 8.) Credits: Tuan Tran and Detlef Lohse. Download video file (MOV)

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  Supplemental Video 11: Impact of a water drop at We = 16 on a solid at 500°C. Tiny droplets are ejected above the thin film that forms at impact. (This corresponds to the spraying-film-boiling regime in Figure 8.) Credits: Tuan Tran and Detlef Lohse. Download video file (MOV)

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  Supplemental Video 12: Linke’s device: A water drop on a hot ratchet self-propels, in the direction toward the steep part of the teeth. Credits: Guillaume Lagubeau and David Quéré. Download video file (AVI)

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  Supplemental Video 13: Approaching a piece of dry ice from a hot ratchet on which glass beads were deposited shows that the flow vapor is rectified by the ratchet: It mainly takes place in the direction toward the step, which suggests that the Leidenfrost body above is entrained by the vapor flow (viscous entrainment). Credits: Guillaume Dupeux, Christophe Clanet, and David Quéré. Download video file (AVI)